Stretching die for sheet metal



March 29 1927. 1,622,590 ,'r. JoLsTAD STRETCHING DIE FOR SHEET METALFiled May '7, 1923 4 Sheets-Sheet 1 llllllll/ /lllllllllll INVENTOR.Tryin@ r1'a2sa" ATTORNEYS March 29,1927. 1,622,590

- T. JoLsTAD sTnETcHING Dm FOR SHEET METAL FiledMay v, 192s4ksneets-s`heet z INVLNTR. 7;;3/0 71 rfal 5 fa l ZM. #um am A ATroRzvEl/y March 29 1927. 1,622,590

T. JQLSTAD l STRETCHING- DIE FOR SHEET METAL Filed May v. 1925 4sheets-sheet s g f f4 f f7 0 5/1 w A INVLNToR. 2/ "Y Z3' A Y 63" BY Wi/arLsac g a HSM ATTORNEYS March 29, 1927.

.I -T. JoLsTAD sTRETcHING DIE FOR SHEET METAL Filed May '.7,

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NVENTOR. Try-fra 1752s fad' Patented Mar. 29, 1927.

TRYsvn JoLsTan, or DETROIT, MICHIGAN,

PANY, or DETROIT, ments-AN,

ASSIGNOR T MICHIGAN STAMENG COM- A CGRPORATEON GF MICHIGAN.

STRETCHING; FOR SHEET METAL.

Application filed May 7 This invenion relates to dies for stretehing andshaping sheet metal.

An object of the invention is to provide a simple land effective devicefor holding the metal so that it will not slip while it is being shapedto the desired form.

Another object is to provide reliable and practical means for clampingthe jaws upon the metal while at the same time permitting the jaws toslider during the operation of thc die.

Another object is to provide means for normally retainino' the jaws inretracted position and for regulating the sliding movement thereofwhereby the metal will be shaped properly by the die.

lith the above and other objects .in view7V the invention consists ofcertain novel features of construction, combinations and arrangeu'ientsof parts as .will be more fully described and particularly pointed outin the appended claims;`

ln the accompanying drawings :j-

Fig. l is a fragmentary front elevation of a press and showing parts insection;

Fig. Q is a perspective view of the .bed plate and supporting frame forthe jaws; Fig.l 3' is a sectional view takenon line 22 of Fig. 2;

Fig.k l is an enlarged vertical sectional view through the bed-plate,frames and dic and showing lthe jaws in elevation; and

Figs. 5, (l, and 7 are. views similar to Fig. 4; but showing a slightlymodified construction.

With certain constructions now in use, a reciprocatory holder isemployed to clamp the sheet metal directly upon the bed plate so thatthe metal is permitted to slide 'over the edges lsurrounding the centralopening in the bed plate when the die is operated to shape the metal.However, it has been found that the metal very often slips while beingshaped with the die with the result that the metal is shaped improperly.It has also been found that it is necessary to provide relatively widesheets of metal so thatl there will be suiflcient bearing surfaces atythe edges thereof for engagement with the bed plate to prevent the metalfrom being pressed entirely through the opening therein when the die isoperated. Furthermore, Such constructions are objectionable -forv thereason that after the metal has been shaped, the

1923. Serial No. 637,371.

'2 which preferably provided with a central opening r3 and an integralhorizontal frame et to receive the die or plunger 5 for stretching themetal. This die may be any shape desired and any suitable means may beemployed for actuating the same' The sheet of metal to be shaped ispreferably held in proper position over the frame l by means ofaplurality of sets of comple ment-ary elongated jaws 6 and which areprovided with teeth 8' that grip the metal at its `opposite edges. Thejaws 6 of each set may be mounted on any two of the side bars 9 of theframe and preferably entend longitudinallyv thereof while thecomplementary cti-operating jaws 'l' of each set are preferably providedwith rearwardly ent-ending lugs 'l0 that are mounted on horizontalpivots 1l extending through spaced lugs l2 on the jaws G. The jaws@ areadapted to slide over spaced parallel elongated trans' versely extendingrecesses 13 in the upper surface 'of `the side bars of the frame and arepreferably prwided with laterally ein tending ribs l/l that engageinverted substantially l.-sliaped guides l5 detachably secured to theframed, while the jaws 7 are normally held in r ised position withrespect to the aws 6 by means of coil springs 16 engaging recesses inthe opposed faces of vthe jaws. Yoles 1T extend downwardly from rearwardextensions 18 on the jaws 6 and embrace spools 19 that are slidablymounted on bolts 2O extending longitudinally of the recesses 13 in theframe. Coil springs 2l surround the bolts between the spools andtheinner ends of the recesses 13 and norn'ially retain the jaws spaced fromthe inner edges of the frame l. j

Any suitable means may be employed for clamping the pivoed jaws 7 uponthe metal and for holding the said' jaws in clamped position during theoperation of the die, while at the same time permitting the jaws 6 and'l' to slide inwardly. As shown, a vertically movable horizontal frame22 sur rounds the die and is adapted to move the pivoted jaws 7downwardly against the tension of the springs 16 to clamp the metal uponthe jaws 6. The frame 22 may be actuated by any suitable means (notshown) and the movement thereof is preferably timed with relation to thedie 5 so that the frame 22 will clamp the pivoted jaws 7 upon the metalbefore the die is moved downward. Likewise the die .may be movedupwardly in advance of the frame 22.

In use, a sheet of metal may be placed upon the jaws 6 and the frame 22may be lnovec downwardly to clamp the jaws 7 upon the metal. The die maythen be lowered to shape the metal and during the shaping operation, themetal will be pressed downwardly as shown in Figure 4 which will causethe jaws to slide inwardly between the frames 4 and 22. 1When the die israised the springs 16 will raise the upper jaws 7 and the springs 2lwill return both the jaws 6 and 7 to normal retracted position.

In the modification illustrated in Figure 5, a slightly diiferent formof frame 30 is used. The bars 3l of this frame preferably inclineinwardly and are formed integral with vertical extensions 32 upon thebed plate 33. A die 34, operable in a manner similar to the die 5, isused in this construction and is adapted to move downwardly between theframe 30 and the extensions 32 upon the bed plate to stretch the metalto the desired shape. The metal to be shaped is adapted to be gripped atits opposite edges by means of jaws 35 which are slidably mounted on thebars 3l of the frame in a manner similar to the jaws 6 while jaws 36 arepivoted upon the jaws 35 in a manner similar to the jaws 7 and arenormally spaced therefrom by means of coil springs 37. The jaws 36 areadapted to be clamped upon the metal by means of a frame 33 which isprovided with inclined portions 39 for engagement with the jaws 36 andwhich is movable vertically similar to the frame 22. The inner ends ofboth the jaws 35 and 36 are inclined as shown at 40 and 4l respectivelyso that they will be in alignment with their sides 42 of the eX-tensions 32 when the jaws are moved inwardly. Coil springs 43 arelocated in the recesses 44 in the frame bars supporting the jaws andengage depending lugs 45 upon the jaws 35 to normally retain the same inspaced relation to the inner edges of the frame 30.

In the modification illustrated in Figure 6, the die 50 is preferablystationary and is mounted upon a bed plate 51 which is supported uponchannel members 52 that are secured to a suitable base 53. The frame 54for supporting the jaws 55 and 56 surrounds the die 50 and is movablevertically with resp-ect to the bed plate. The jaws 55 are slidablymounted on the frame in a. manner similar to the jaws 6 and are similarin construction, while the jaws 56 are pivoted upon the jaws 55 in amanner similar to the jaws 7 and are normally spaced from the jaws 55 bymeans of coil springs 57.

A plurality of arms 58 are secured io the frame 54 and extend downwardlythrough openings 59 and 60 respectively in the flanges 6l of the die andin the bed plate. These arms are connected at their lower ends to aplate 62 which is located beneath the bed plate 5l and between thechannel menibers. Coil springs 63 are located between the base 53 andthe plate 62 and normally retain the latter in engagement with the bedplate. The jaws 56 are adapted to bc clamped upon the metal by means ofa frame 64 which is also adapted to move the jaws 55 and 56 as well asthe frame 54 downwardly against the tension of the springs 63 toward thebed plate so that the metal clamped by the jaws will be forced over thedie and will be shaped accordingly. Any suitable means (not shown) maybe employed for operating the frame 64.

In th-e modification illustrated in Figure 7 a construction is shown forstretching a sheet of metal so as to remove all crimps and unevensurfaces preliminary to shaping the same. In detail, a horizontal framesimilar in construction to the frame 4 is formed integral with a bedplate 7l which is similar in construction to the bed plate 2. Jaws 72are slidably mounted on the frame 70 in a manner similar to the jaws 6and are preferably similar in construction, while cooperating jaws 73are pivoted upon the jaws 72 and are preferably similar in constructionto the jaws 7. The jaws 73 are adapted to be clamped upon the metal atthe edges thereof by means of a frame 74 which may be moved verticallyby any suitable means (not shown).

The jaws 72 and 73 are adapted to be moved outwardly to stretch themetal and for this purpose I preferably provide substantially L-shapedfingers 75 which are detachably secured to a vertically movable frame 76and which are provided with inclined outer surfaces 77 at their lowerends for engagement with the outer walls of vertical openings 78 inhorizontal arms 79 extending rearwardly from the jaws 72 intermediatethe ends thereof. Any suitable means (not shown) may be employed formoving the frame 76 and fingers downwardly to cause both of the jaws 72and 73 to be moved outwardly so that the sheet of metal clamped therebywill be stretched.

Thile it is believed that from the foregoing description, the nature andadvantages of the invention will be readily apparent, I desire to haveit understood that I do not limit myself to what is herein shown and llldescribed andmthaft such 'clial1-igea'd may fberesortedfto when .desiredslfalili within fthe-f scope ofwliattiisl:claimefdw-` What vI claim=asrimy invention is 1. Inl a devicefoit'hc class deseribed,"az plu-Arality'fof opposed lslidablymountedjaws for* clamping'the metal to 'bestretched; asupportif-f 'for said jaws, means for actuating oneiofrsa-id jaws tof'clafm'p Fthe i metall while at ,the

same timeh permit-ting said `'fjaws to 1"- 1nove f upon` said supportwith the metalin-"a' dir' e tion substantiallytransve'rsetol-the'ildireetion off 1 stretching of f the smet-al and meansifAvsaid` vframe,'guides for said jawsdtachablyf secu-red' tp saidiframe;jawspivotallymountr ed-o'n saidislidablyjrnotintedI jawsiandfada'ptf ed 'to' 1coop,eratethere'v'vith to lclampthe meta-l;

"i, means' #for normally "retaining/ saidifpivotec'l '-70 jawsfin raisedposition, means for clamping sai-d'1 pivoted"jawsiuponsaid drietal,afdie'and* meansiorshapingthenetal about the `die'.'." 7, In a press forIworking sheetimetal; the

,-11 of-.s'etsfof' complementary jaws slidablymounted onsaidbed-plateaty-oppoi site sideswf.- said opening, yieldable meanscarried ,hywsaid support lfor `regulatingttheynorrnallyl-v separatingthe complementaryv slidingunovement ofisaidffjaws'r` j 2. In a device ofthefclas'sdes'cribed, apl'ulrality `of -co-'operat'ingvjawsfor-'fholdlng the@ metal to be shaped therebetween, framem llingpivotedfu lfo'iic lampir'i'g said vcomplementaryjaws upon when-saidjaws-'are -closedf 1` 8'. In'J a press for w'orkiiigsheet metah'thefI n'combination with 'a beidlplate', 'of` means onf-85 thebedfiplatej for'holding the sheet metal to beisha'ped `4l`including a plurality? ofsets fai* f opposed slidably mounted compllen'ien'tary .j jaws, eachset comprising a lower jaw and a ponsaid'lower jaw, andfmeans"theivmet'al'before it is'shapedLj" 9% "In a pressfor*working'sheetimetalgthe" ralityfof opposedslidablymounted-jiaws-fofmeans'onthe bedlplate for holdingth'e sheetsupportingithe* metal Ito bei` stretched, pivot-"fi" ally mounted; jaws?adaptedft'o cooperate gwitlir l y`setsf-'fofk "comple the: slidablymounted jaws for hold-'ing the? metal, yieldableA means jl for normally'f ietain' ingathe` lastfmentioned fjawlsini spaced rela'ljawfantly'apivotallymountedupper jaw? 100G@ and means for -movingjthepivot'ed'jawsof clamping the `pivota'lly mounted jaws*gup'on""lL`thefmetal., ra' die, 'andI lmean'sf'forljrelatiyey?1 ino-ving fthe a diei andy` sheetmetall for shaping 7 the metals:y j

4. In a device "ofi italie*l class -eles'c'ribredfg-^f opl?i posedLslidably 1mefuntedjaws'=forf,s'upperti1gthe metal:ton-bestretched-gpivotally mounted jaws adapted to cooperate with the jaws aforesaid toclamp the metal, yieldable means disposed between the jaws aforesaid fornormally retaining the pivotally mounted jaws in raised posit-ion,reciprocatory means for clamping the pivoted jaws upon the metal, a die,and means for shaping the metal about the die.

5. In a device of the class described, a pair of frames, opposedjawsslidably mounted on one of said frames for supporting 'the metal to bestretched, jaws pivotally mounted on the jaws aforesaid and adapted tocooperate therewith to clamp the metal, yieldable means for normallyretaining the pivoted jaws in raised position,- means for moving theother of said frames to clamp the pivoted jaws upon the metal, a die,and means for shaping the metal about the die.

6. In a device of the class described, a frame, opposed jaws slidablymounted upon Lfor;ih t'jidlng j 'the@metalI to 'bef' shaped', meansfore' claiipingsaid jawsl upon said j'inetal befl foe'it isshap'edwhile`at"the"samef'ti1ne peri mitting said jaws to move with themetal when said metal is being shaped, the ldirection of movement beingsubstantially transverse to the direction of shaping of the metal, andmeans for regulating the movement ofl said jaws.

11. In a device of the class described a pair of jaws pivotallyconnected to each other for clampingr the metal to be stretched, meansfor normally separating the jaws of said pair, a frame supporting saidjaws, means for actuating one of said jaws to clamp the metal before itis stretched while at the same time permitting said jaws to slide uponsaid frame while securely clamped tothe metal, and yiel'dable means forregulating the sliding movement of said jaws.

12. In a device of the class described, the combination with asubstantially horizontal frame for supporting the work, and asubstantially vertically movable die for engagl jaws ofieach set, meansvfor closing the jaws combinationlafwith a bedpla'te'of iijiovable'95 ifing the work, of means for holding the work including pairs of opposedjaws slidably mounted upon the upper face of said frame, means formaintaining said jaws in engagement with the work during a predeterminedmovement of the die, and means for lauto-v matically releasing the jawsfrom the work when said die reaches a predetermined position.

13. In a device of the class described, the combination with avertically movable die for shaping the work, a substantially horizontalframe having a central opening -for receiving the die, and areciprocating frame above the frame aforesaid, of means for holding thework including reciprocating jaws on said first-mentioned Jframe movablealong lines extending from the outer edges of said frame to the edges ofsaid opening, and cooperating jaws pivotally mounted upon thereciprocating jaws in such away as to be moved automatically by thereciprocating frame aforesaid into engagement with the work. j

14. In a device of the class described, .the combination with astationary frame land a reciprocating frame, of means for holding thework upon the first-mentioned frame including reciprocating jaws on saidfirstmentioned frame movable alonglines extending from the outer edges:of said frame toward the center thereof, and cooperating jaws pivotallymounted .upon the reciproeating jaws in suchv a way as to be movedautomatically by the reciprocating Vframe into engagement with thework.s

l5. In a device of the class described, a frame having an opening at thecenter thereof for receiving a reciprocating die, means for holdingsheet metal to be shaped over said opening including reciprocating jawsVon said frame, and cooperating pivotally mounted jaws carried by said,reciprocating iaws, yieldable means normally maintaining frame having avertical opening therein, and

a substantially vertically movable reciproeating die movable into saidopening7 of means for holding the work including reciprocating jawsmovable over the upper face of said frame along lines extending from theouter edges of said frame to the edges of said opening.y

17. In a ydevice of the class described, a frame having an openingtherein for receiv- Ling the work whileit is being shaped, and

means engageable with the work for shaping the same, and means forholding the work including reciprocating jaws movable over the upperface of said frame along lines extending from the outer edges of saidframe to the edges of said opening.

18. In a device of the class described, the combination with asubstantially horizontal frame having an opening therein for receivingthe work while being shaped, and means for shaping t-he work, of meansfor holding the work while being shape-d including jaws movable over theupper face of said frame along lines extending from the outer edges ofsaid frame to the edges of said opening, and means associated with saidshaping meansfor maintaining said jaws in engagement with the work whilethe latter is being shaped, said last-mentioned means permitting saidjaws to move over said frame along the lines speciiied while beingshaped.

In testimony whereof I aflix my signature.

TRYGVE JOLSTAD.

